Just like the work of an automobile engine, for example, the power provided to the automobile is reduced due to carbon deposition and poor combustion of the spark plug, which is the situation that leads to yang deficiency (energy reduction).

For the time being, yin deficiency means that the fuel tank is almost empty.

So how to solve it? Nourishing yin (just refueling) and strengthening yang? By cleaning the spark plug, this dredging method can be realized.

Go on, it's more complicated. What if the fuel tank leaks? It's no use just refueling. You have to fill the leak first, so does the body yin deficiency.